PXIE-5663 Datasheet, PDF (3/8 Pages) National Instruments Corporation – Vector Signal Analyzer

Vector Signal Analyzer
RF Record and Playback
You can combine an NI PXIe-5663/5663E RF vector signal analyzer with a PXI RF
vector signal generator for record and playback applications. In this application,
you use an NI PXIe-5663/5663E to continuously record an RF signal as a file on a
redundant array of inexpensive disks (RAID) volume. Then you use an RF vector
signal generator to stream the recorded waveform from disk. With a 2 TB RAID
volume, an NI PXIe-5663/5663E can be used to stream 50 MHz of RF bandwidth
continuously to disk for more than 1.5 hours.
Because of the vector signal analyzer’s PCI Express data bus, you can also use
multiple analyzers to stream data to disk. With more than 1 GB/s of total system
bandwidth, you can stream more than 100 MHz continuously to disk using
multiple analyzers.
Phase-Coherent Analysis
The flexibility of the NI PXIe-5663/5663E modules enables multiple instruments
to share a common start trigger, a reference clock, and even an LO. As a result,
you can synchronize at least four NI PXIe-5663/5663E RF vector signal analyzers
for phase-coherent acquisition. A block diagram of two synchronized analyzers is
shown in Figure 4.
NI PXIe-5601
NI PXIe-5622
ADC
NI PXIe-5601
NI PXIe-5622
ADC
Figure 5. ACP Measurement of a QPSK Signal
This example uses a 3.84 MS/s symbol rate and a root raised cosine filter
with an alpha of 0.22. A filter length of 128 symbols was implemented. The
stimulus used in this measurement was programmed to an RF power level of
-5 dBm. As Figure 5 shows, you can use an NI PXIe-5663/5663E to measure up
to -65 dBc of adjacent channel rejection with the described settings.
In addition, with the high dynamic range and phase noise performance of the
NI PXIe-5663/5663E modules, you can analyze higher-order modulation schemes
such as 256-QAM. A loopback configuration with NI PXIe-5673/5673E RF vector
signal generators and an NI PXIe-5663/5663E yields a nominal EVM (RMS)
measurement of 0.5 percent. The constellation plot is shown in Figure 6.
NI PXI-5652
Figure 4. Simplified Block Diagram of Cascaded NI PXIe-5663 RF Vector Signal Analyzers
As shown in Figure 4, the NI PXIe-5601 RF downconverter both accepts and
distributes a buffered LO. In this configuration, you can synchronize up to four
analyzer channels without significant degradation of RF performance.
High-Performance RF Measurements
Using a 16-bit ADC with a high-performance RF front end, NI PXIe-5663/5663E
modules offer up to 80 dB of spurious-free dynamic range (SFDR). Thus, you can
perform spectrum analysis measurements that require high dynamic range. In
Figure 5, an ACP measurement of a QPSK modulated signal is shown.
Figure 6. Constellation Plot of 256-QAM
The settings used in Figure 6 include a center frequency of 1 GHz, a 5.36 MS/s
symbol rate, and a 0.12 root raised cosine filter alpha. The test stimulus was
generated with the NI PXIe-5673 using the same symbol rate and filter alpha
settings at an RF power level at -10 dBm.
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